feat(stm32mp2-fdts): add fw-config files for STM32MP257F-EV1

Add the Firmware Config DT file for STM32MP257F-EV1 board.

Signed-off-by: Yann Gautier <yann.gautier@st.com>
Change-Id: I895ef919b1f388be1e8d25490f25b1e7195984f8
2 files changed